Study: Some strains of E. coli better at living on plants than in animals

Typically residing the mammalian gut, some strains of E. coli have taken on a new lifestyle, making them more at home on plants, according to new research.

As part of the study, the U.K.’s Institute of Food Research took more than 100 isolates from the leafy bits of plants in England. The samples were analyzed and indicated a diverse range of E. coli strains living on the plants. Once the strains were known, they were compared against types of E. coli taken from the guts of mammals.

One of the biggest differences they found was E. coli found on plants tend to form biofilms (colonies of bacteria that form a film – think of the goop that forms on the rubber flaps in sinks with garbage disposals) more easily than do strains from the gut. These films are held together by a mix of protein and sugar, which E. coli found on plants are more likely to produce, according to the research.

The study also found E. coli derived from plants had more of a sweet tooth for sucrose and other sugars than E. coli derived from mammals.

The increased likelihood of biofilms and intake of sugars are survival mechanisms for living outside of the warm, moist environment of the gut.

So why does this matter? Well, for one it provides researchers with additional information on how potentially dangerous strains of the common gut bacteria have adapted to survive on other organisms, such as plants (including fruits and vegetables).

Although many strains of E. coli are harmless and naturally found in the gut, some strains such as E. coli O157:H7 can produce severe foodborne illness.

“While it was known that different environments harbored different E. coli populations, we now have an idea on how and why this happens,” researcher Sacha Lucchini said in a statement. “Knowledge of the mechanisms involved in plant colonization by E. coli provides targets for developing strategies aimed at preventing potentially dangerous E. coli strains from colonizing vegetables, thus keeping them off our plates.”